Lens barrel with MEMS actuators

Abstract

A lens barrel for, e.g., a miniature camera or another device, includes an annular barrel, a plurality of first optical elements disposed coaxially within the barrel, an actuator device disposed coaxially within the barrel in front of the first optical elements, a front cover attached coaxially to a front surface of the actuator device, and a second optical element mounted coaxially in a central opening of a moving platform of the actuator device such that rotational movement of actuators in the actuator device causes the moving platform and second optical element to move conjointly with a purely translation movement along the optical axis of the second optical element and relative to the first optical elements.

1. A lens barrel, comprising:
 an annular barrel having a central axis; 
 a plurality of first optical elements disposed in the barrel such that respective optical axes of the first optical elements are aligned coaxially with each other and the central axis of the barrel; 
 an actuator device having a plurality of actuators, each having components that move rotationally relative to each other, a moving platform coupled to each of the actuators by a flexible hinge, and a central opening in the moving platform disposed concentric to a central axis of the actuator device, the actuator device being disposed in the barrel in front of the first optical elements such that the central axis of the actuator device is aligned coaxially with the central axis of the barrel and the optical axes of the first optical elements; 
 a front cover attached to a front surface of the actuator device such that a central opening in the front cover is concentric with the central opening in the moving platform; and, 
 a second optical element mounted in the central opening of the moving platform such that an optical axis of the second optical element is aligned coaxially with the central axis of the barrel, the optical axes of the first optical elements, and the central axis of the actuator device, and such that rotational movement of the actuators causes the moving platform and second optical element to move conjointly with a purely translation movement along the optical axis of the second optical element. 
 
     
     
       2. The lens barrel of  claim 1 , wherein:
 one of the first optical elements immediately adjacent to the actuator device includes a plurality of forwardly protruding alignment pins disposed symmetrically around an outer margin of a front surface thereof; 
 the actuator device further includes a plurality of radial tabs disposed symmetrically around an outer periphery thereof, each tab having an outer circumferential surface and an alignment aperture therein; and, 
 the actuator device is disposed in the barrel such that:
 each of the alignment pins is engaged in a corresponding one of the alignment apertures so as to align the actuator device concentrically with respect to the immediately adjacent optical element; and, 
 the outer circumferential surfaces of the tabs respectively abut an inner surface of the barrel so as to align the actuator device concentrically within the barrel. 
 
 
     
     
       3. The lens barrel of  claim 2 , wherein:
 the front cover includes a plurality radial slots, each exposing a front surface of a respective one of the tabs; and, 
 the front surface of at least one of the tabs is electrically conductive, such that a wire or a flexible circuit board is electrically connectable thereto by way of a bolus of an electrically conductive adhesive disposed thereon. 
 
     
     
       4. The lens barrel of  claim 1 , wherein at least one of the first and second optical elements comprises one or more of a lens, a group of lenses, a fixed aperture, a variable aperture, a shutter, a mirror, a prism, a spatial light modulator, a diffraction grating, a laser, an LED and/or a detector. 
     
     
       5. The lens barrel of  claim 1 , wherein:
 at least one of the first and second optical elements comprises a lens mounted concentrically within an annular lens holder; and, 
 at least one of the barrel, the front cover, the lens and the annular lens holder comprises a plastic material. 
 
     
     
       6. A miniature camera incorporating the lens barrel of  claim 1 . 
     
     
       7. An electronic device incorporating the miniature camera of  claim 6 . 
     
     
       8. The electronic device of  claim 7 , wherein the device comprises a cellular telephone, a laptop computer, a personal digital assistant or a surveillance device. 
     
     
       9. A miniature camera incorporating the lens barrel of  claim 1 . 
     
     
       10. An electronic device incorporating the miniature camera of  claim 9 . 
     
     
       11. An actuator module, comprising:
 a rear cover having a central opening and a plurality of forwardly protruding alignment pins disposed symmetrically around an outer margin of a front surface thereof; 
 an actuator device having a plurality of actuators, each having components that move rotationally relative to each other, a moving platform coupled to each of the actuators by a flexible hinge, a central opening and a plurality of radial tabs disposed symmetrically around an outer periphery thereof, each tab having an outer circumferential surface and an alignment aperture therein, the actuator device being attached to the front surface of the rear cover such that each of the alignment pins is engaged in a corresponding one of the alignment apertures and the respective central openings of the rear cover and the actuator device are aligned concentrically with each other; and, 
 a front cover having a central opening and a plurality of radial slots disposed symmetrically around an outer periphery thereof, the front cover being attached to a front surface of the actuator device such that each of the radial slots exposes a front surface of a respective one of the tabs and the central opening of the front cover is aligned concentrically with the respective central openings of the rear cover and the actuator device. 
 
     
     
       12. The actuator module of  claim 11 , wherein the front surface of at least one of the tabs is electrically conductive, such that a wire or a flexible circuit board is electrically connectable thereto by way of a bolus of an electrically conductive adhesive disposed thereon. 
     
     
       13. The actuator module of  claim 11 , wherein the actuator device comprises a semiconductor. 
     
     
       14. The actuator module of  claim 11 , wherein at least one of the front and rear covers comprises a thermosetting plastic or a thermoforming plastic. 
     
     
       15. A lens barrel incorporating the actuator module of  claim 11 , wherein the outer circumferential surfaces of the tabs respectively abut an inner surface of the lens barrel so as to align the actuator module concentrically within the lens barrel. 
     
     
       16. A miniature camera incorporating the lens barrel of  claim 15 . 
     
     
       17. An electronic device incorporating the miniature camera of  claim 16 . 
     
     
       18. The electronic device of  claim 17 , wherein the device comprises a cellular telephone, a laptop computer, a personal digital assistant a surveillance device. 
     
     
       19. A lens barrel, comprising:
 an annular barrel having a central axis; 
 a plurality of first optical elements disposed in the barrel such that respective optical axes of the first optical elements are aligned coaxially with the central axis of the barrel and with each other; 
 an actuator module disposed in the barrel in front of the first optical elements, the actuator module comprising:
 a rear cover having a central opening and a plurality of forwardly protruding alignment pins disposed symmetrically around an outer margin of a front surface thereof; 
 an actuator device, including a plurality of actuators, each having components that move rotationally relative to each other, a moving platform coupled to each of the actuators by a flexible hinge, a central opening in the moving platform disposed concentric to a central axis of the device, and a plurality of radial tabs disposed symmetrically around an outer periphery thereof, each tab having an outer circumferential surface and an alignment aperture therein, 
 wherein the actuator device is attached to the front surface of the rear cover such that each of the alignment pins is engaged in a corresponding one of the alignment apertures and the respective central openings of the rear cover and the device are aligned concentrically with each other and the outer circumferential surfaces of the tabs respectively abut an inner surface of the barrel so as to align the actuator module concentrically within the barrel; and, 
 a front cover having a central opening and a plurality of radial slots disposed symmetrically around an outer periphery thereof, the front cover being attached to a front surface of the actuator device such that each of the radial slots exposes a front surface of a respective one of the tabs and the central opening of the front cover is aligned concentrically with the respective central openings of the rear cover and the actuator device; and, 
 
 a second optical element mounted in the central opening of the moving platform such that an optical axis of the second optical element is aligned coaxially with the central axis of the barrel, the optical axes of the first optical elements and the central axis of the actuator device, and such that rotational movement of the actuators causes the moving platform and second optical element to move conjointly with purely translational movement along the optical axis of the second optical element. 
 
     
     
       20. The lens barrel of  claim 19 , wherein the front surface of at least one of the tabs is electrically conductive, such that a wire or a flexible circuit board is electrically connectable thereto by way of a bolus of an electrically conductive adhesive disposed thereon.